Many of the investigations included in this project were either multi- center or multi-disciplinary in their approach. A major focus has been on female cancers, with several investigations utilizing biochemical probes to evaluate the relationship of hormonal and nutritional factors to risk of breast and endometrial cancers. Of particular interest have been the effects of oral contraceptives on the risk of premenopausal breast cancer and of combined estrogen/progestogen therapy on cancers of the breast and endometrium. The risk of endometrial cancer has also been examined in relation to reproductive and medical factors, as well as smoking. The relationship of the human papillomaviruses to risk of cervical neoplasia has been of major interest, with several natural history studies underway. These studies were preceded by several methodologic studies to determine the persistence of viral infection over time. Multidisciplinary studies of cancers of the nasopharynx have clarified the relationship of risk to the presence of Epstein-Barr virus and to a variety of medicinal and chemical exposures. Data from case- control studies of leukemia and non-Hodgkin's lymphoma suggest a relationship of risk with use of several insecticides. An association of reproductive factors with risk of cancers of the bladder, brain and colon has also emerged. Follow-up studies have also been conducted to evaluate the relationship of cancer risk to different types of gynecologic operations and to a variety of immunologic disorders, with rheumatoid arthritis of particular interest. Descriptive analyses have also examined trends in vulvar, bladder and cervical cancer, the latter focusing on reasons for the racial disparity in rates.